IL6 and hereditary pheochromocytoma-paraganglioma: Since pheochromocytoma may produce adrenocorticotropin, insulin-like growth factor 2, somatostatin, growth hormone-releasing hormone, corticotropin-releasing hormone, and interleukin 6, it was considered, however, that it might also stimulate the adrenal cortex to hyperfunction and proliferation through the paracrine pathway (21).